This is a fan fiction rendition presenting an alternate version of the Imperial assassin M’Shen whom slayed the traitor Primarch Conrad Curze. I feel she was not given her due respect.
...
"Let it be said I am not a slayer of Gods but you are not even a Demi-God, nothing more than a debased and depraved killer of innocent. You fought to preserve your life but have failed."
= Officio Assassinorum Project Paragon-Parabellum=
Assassins are able to change the fate of worlds with the pull of a single trigger. Where the length of the Emperor's reach needs to be made abundantly clear, a Vindicare sniper will put a bullet in the target's head whilst the errant individual is surrounded by his followers. If the traitorous creed has spread to an entire organisation or military force, an Eversor will instead be set loose; a bio-enhanced berserker that will slaughter dozens if not hundreds of rebels alongside the key individual he has been sent to slay. Should the deed require more subtlety, an operative from the Callidus Temple will instead be despatched; in such cases it is all but impossible to detect the presence of these shape-shifting Assassins until the deed is done. If the target is a psyker, one of the rare and fearsome Culexus will be sent to hunt them down, beings with a strange void in place of a soul that makes them the bane of all who treat with the Warp.
Twin children, one a boy (Paragon) and one a girl (Parabellum), were both genecrafted for a special purpose. Split apart at birth never to know each other one was seeded with psychic essence, the other with the Pariah gene. They were both special even for the strict specifications required by the Imperial assassin creed. Both were trained learning skills from various temples Callidus, Venenum, Culexus, Vindicare, Eversor and Vanus rather than just one as was usual. Noted with a talent for brutal destruction eventually the twins were sent upon their first training missions. Rumors exist that one slew a Primarch from one of the expunged Legions.